The skinny on milk and diabetes

There are currently controversies surrounding the consumption of milk as well as which forms to consume. Annica Rust gives us the facts and clears up any confusion.

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Benefits of dairy (milk)

Dairy is a versatile food item, with numerous benefits, such as shown in Figure 1. Diary contains all the macronutrients, including carbohydrates, fats and protein as well as vitamins and minerals.¹

Dairy contains fat-soluble vitamins A, D and E as well the water-soluble B-complex vitamins and vitamin C. The fat content of milk will determine the number of fat-soluble vitamins, therefor the amounts may differ in low-fat and fat-free milk. Although the fat component is removed in low-fat or fat-free milk, some manufactures will fortify milk, with vitamin A & D.^1,3

Dairy is also an excellent source of calcium and contains minerals, such as phosphorous, magnesium, potassium and zinc.^1,3 One serving of dairy (250ml milk, 200ml yoghurt or 40g cheese) contains 300mg of calcium. This is a large portion of the daily recommended allowance for adults, which is 1000-1200mg of calcium per day. The role of each component can be viewed in Figure 1 below.¹

Food and dairy matrix

Food is more than simply nutrients. We don’t eat individual nutrients (vitamins and minerals), however, we consume different food items in a variety of meals which contain the nutrients our bodies require.¹

The unique food structure can influence the digestion and absorption of nutrients. Milk fat globule membranes (MFGM) may have a significant influence on the digestion of dairy and the absorption of dairy fat. MFGM may prevent the negative effect of saturated fatty acids on low-density lipoprotein (LDL) cholesterol, or simply known as the bad cholesterol, but the protective effect needs to be further investigated. The structure of milk and fermented dairy will also have a positive effect on digestion and absorption. This may partially explain why the benefits of whole foods will always exceed supplementation.¹

 

Milk and diabetes

A positive association has been found between dairy, more particularly low-fat or fat-free dairy and the risk of diabetes. The positive effect may be contributed to the food matrix which suggests that the combination of nutrients in dairy seem to have a more positive effect for people living with diabetes when compared to individual nutrients. The calcium, magnesium, vitamin D and whey protein in dairy may all through different mechanisms of action play a role to lower blood glucose levels.¹

 

Milk and cardiovascular disease (CVD)

People with diabetes have an increased cardiovascular risk which can’t be ignored. High cholesterol and high blood pressure as well as unhealthy lifestyle factors (obesity, inactivity and smoking) are common risk factors associated with CVD.

The intake of saturated and trans fatty acids have a significant impact on increasing LDL cholesterol levels. Dietary strategies will therefore aim to substitute saturated fat with polyunsaturated fatty acids as shown in Table 1.

Table 1: Types of fats

Saturated fat	Trans-fatty acid	Polyunsaturated fats Omega-3                         Omega-6
Triglycerides in which most of the fatty acids are saturated	Fatty acids with hydrogen’s on opposite sides of the double bond	Polyunsaturated fatty acid in which the first double bond is 3 carbons away from the methyl end of the carbon	Polyunsaturated fatty acid in which the first double bond is 6 carbons away from the methyl end of the carbon
Visible fat on meat Skin of the chicken Bacon Butter Chocolate (cocoa) Coconut Cream cheese Cream Lard Full cream milk products Sour cream Coconut, palm oil	Fried foods Commercially baked foods (cakes, cookies) Snack food (chips, crackers, microwave popcorn) Margarine (hydrogenated)	Fatty fish (tuna, salmon, herring, mackerel) Walnuts Flaxseed	Pumpkin and sunflower seeds Oils (corn, sunflower, cottonseed) Mayonnaise Margarine (nonhydrogenated)

 

Products that are higher in fat also tend to be high in saturated fats, dietary recommendation will therefore recommend low-fat or fat-free dairy, to reduce saturated intake. The difference in milk can be seen in Table 2.

Table 2: Comparison of milk per 100g/ml

	Full Cream	Low Fat	Fat Free
Energy	256	190	160
Protein	3.3	3.3	3.4
Carbohydrate	5	4.8	4.8
Of which Sugars	4.1
Total Fat	3.3	1.5	0.5
Of which mono unsaturated fatty acids	1	0.4	0.0
Of which poly unsaturated fatty acids	0.1	0.0	0.0
Of which saturated fatty acids	2.2	1.1	0.5
Of which trans fatty acids	0.1	Trace	Trace
Cholesterol	11	8.4	0.0
Dietary Fibre	0.2	0.0	0.0
Sodium	39	44	44
Calcium	117.5	122	123

The recommendation is to aim for less than 1.5g per 100g of saturated fats (Table 3). However, based on the food matrix dietary, approaches can be more open to move away from nutrient-based approaches and to move more toward food-based dietary patterns (looking more at your diet as a whole vs one single food items). But most importantly dairy intake shows to have a protective to neutral effect on CVD risk.¹

Table 3: Recommended fat and saturated intake

NUTRIENT   Per 100g	Total Fat	Saturated Fat
HIGH: Avoid – Eat occasionally	> 20g	> 5g
MODERATE:  Eat seldom	3 – 20g	1.5 – 5g
LOW: Healthier option -Eat often	< 3g*	< 1.5g

*Milk, yogurt and ice-cream products, the aim is for less than 2g of saturated fats per 100g. For cheese, the target is for less than 15g of saturated fats per 100g.             

Milk and glycaemic index (GI)

Dairy contains lactose, which is the main carbohydrate in milk. Low-fat dairy has a low glycaemic index and is ideally used in combination with other foods items for meals or for a snack.¹ Visit the GI foundation site to look at endorsed products.

Visit www.gifoundation.com/food-list/dairy/²

Conclusion

 

There are numerous factors to take in consideration when deciding whether full cream, low-fat or fat-free milk or dairy will be most beneficial for your health. It therefore remains the best to contact a registered dietitian for individualised advice.

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References:

1. Rediscover Dairy: https://www.rediscoverdairy.co.za/evidence-based_reviews/
2. The Glycemic Index Foundation of SA: https://www.gifoundation.com/food-list/dairy/
3. Mahan, L.K. & Raymond, J.L. (eds).2017. Krause’s food and the nutrition care process. 14th ed. St Louis. MO: Elsevier Saunders.

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